Field of the Invention
The present invention relates to a wireless power transfer technique.
Description of the Related Art
Recently, the development of techniques of wireless power transfer systems is being extensively made. A power transfer system in which a power transmitting apparatus transmits power to a plurality of power receiving apparatuses is described in Japanese Patent Laid-Open No. 2011-019291. Japanese Patent Laid-Open No. 2011-019291 describes that charging is rapidly completed by prolonging the power transmission time for a power receiving apparatus having a high priority level based on priority level information of each power receiving apparatus.
When the power transmitting apparatus is driven by a battery, the battery remaining capacity of the power transmitting apparatus decreases in accordance with power transmission to the plurality of power receiving apparatuses, and a transmittable power amount also decreases. In this case, if the power transmitting apparatus keeps transmitting power to a given power receiving apparatus, it becomes impossible to transmit power to other power receiving apparatuses. If there is a power receiving apparatus for which power transmission is desirably preferentially performed, the battery remaining capacity is reduced by power transmission to other power receiving apparatuses, and this makes it impossible to transmit power to the preferential power receiving apparatus.
The present invention has been made in consideration of the above problem, and controls the amount of transmission power for each power receiving apparatus in accordance with the battery remaining capacity.